FIELD OF THE INVENTION
The invention relates to an apparatus for cleaning a rotor revolving in a rotor housing of an open-end spinning unit, having a scraper that can be positioned in a fiber collecting groove of the rotor.
Such apparatuses are known from numerous publications.
German Published, Non-Prosecuted Application DE-OS 26 18 094 A1, for instance, describes a cleaning apparatus disposed in an automatic maintenance unit, which has a scraper element that is drivable into the spinning rotor and is adapted to the contour of the fiber collecting groove. The scraper element is secured to one end of a rod. The scraper element also has an injection device for a liquid cleaning agent. Through the use of such a device, the fiber collecting groove can be mechanically cleaned, and in addition a mixture of cleaning agent or detergent and air can be blown into the rotor.
A cleaning apparatus which was especially conceived of for small rotor diameters is known from German Published, Non-Prosecuted Application DE-OS 39 11 946 A1. The actual cleaning apparatus is disposed in a housing, which is positioned in front of the opened spinning box. A carrier is supported pivotably inside the housing, with its pivot axis being offset from the rotor axis and inclined at an acute angle. The carrier is given a three-dimensional shape in such a way that the end occupied by the cleaning tool, when rotated about the axis, describes a circular arc that intersects the plane of the fiber collecting groove of the rotor.
In a forward-oriented motion, the cleaning tool is moved through the rotor opening to the part of the rotor to be cleaned.
A cleaning device is also known from German Published, Non-Prosecuted Application DE 37 15 934 A1, corresponding to U.S. Pat. No. 4,897,993. Its scraper, which is disposed on the end of the piston rod of a pneumatic thrust piston mechanism, is movable in the direction of the fiber collecting groove into the rotor of an open-end spinning unit. The scraper has a knife-like end piece that extends into the fiber collecting groove and is bent in the plane of the knife in such a way that counter to the direction of rotation of the rotor, the front edge extends in inclined fashion counter to the direction of rotation of the rotor.
In both German Patent DE-PS 26 29 161 C2 and German Published, Non-Prosecuted Application DE 33 13 926 A1, cleaning devices for rotor spinning apparatuses are also described that have rotatably supported cleaning tools. Scraper inserts that are positioned at their ends on spiral springs are used as the cleaning tools. During the cleaning process, under the influence of centrifugal force, the revolving scraper inserts press into the rotor groove and clean it of any dirt particles adhering to it.
Since the position of the scraper inserts is radially adjustable because of their disposition on the elastic spiral springs, there is automatic compensation for abrasion from wear of the scraper inserts.
However, that kind of elastic support of the cleaning tools has the disadvantage of the danger that the scraper elements will not be positioned far enough forward, or will bounce back, if firmly adhering contamination is present. In those cases, perfect cleaning of the fiber collecting groove of the spinning rotor is not assured.